Research into real-time energy management on old gold mines

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Abstract

The South African Electricity Supply Industry is one of the backbone industries in South
Africa. During 2003, it became clear that the demand for electricity in South Africa was
increasing at a rate that had not been predicted nor recognised before. This was a clear
indication that Eskom, the national electricity supply utility, would have to invest in
additional generating capacity before 2007.
Eskom envisioned these problems and introduced a DSM programme, which is aimed at
reducing the national peak power demand. In so doing, the immediate need for additional
power generating capacity will be postponed. A major part of this program is the concept of
electrical load shifting.
In 2000 mining in South Africa consumed 29% of the total quantity of electricity generated,
of which the gold-mining industry consumed more than half. Electricity is the exclusive
power source for the application of vital health and safety-related requirements in gold
mines. In some cases, these consume in excess of 55% of the total electricity used on a
mine. Water-pumping systems are a major part of these important applications.
This dissertation presents a study of certain aspects of real-time energy management on
old gold mines, by focusing on electrical load shifting on underground water pumping
systems. Old gold mines use old, proven and energy-intensive methods that were not designed to conserve energy. This study also researches the challenges associated with
the implementation of energy management strategies on old gold mines.
Research was done on three old gold mines to determine the potential for load shifting on
the underground water pumping systems of old gold mines. Integrated simulations were
used as the main method of establishing this potential as well as the financial savings
potential for the client. The simulation results showed large amounts of load-shifting
potential for all three case studies and substantial financial savings potential for the clients.
Real-time, load-shifting strategies were implemented on the three systems analysed in the
case studies. The results generated by these strategies showed that load shifting could be
realised on these systems, and confirmed the potential calculated in the simulations.
Further research into the results however showed that the old infrastructure in the old
mines caused many problems and influenced the sustainability of these strategies.
From this study, the conclusions were made that; (a) there exists a potential for energy
management on old gold mines, (b) there exists large potential for the implementation of
sustainable energy management strategies on old gold mines, and (c) it is feasible to
implement energy management strategies on old gold mines.